Identificação do agente causal do tombamento em coentro em Lagoa-Seca - PB

Abstract

Coriandrum sativum L. is a crop of great importance in Brazil, mainly due to its use as seasonings in Northeastern recipes and income generation for small producers. Thus, studies on the possible diseases that can affect their development, become essential to obtain good agronomic results for this crop. In this context, the present work aimed to identify the causal agent of rotting and tipping in coriander plants in rural properties of Lagoa Seca - PB. The experiment was conducted at the Phytopathology Laboratory of the Federal University of Paraíba. For the experiment, samples of coriander plants with symptoms of tipping were collected in rural properties of Lagoa Seca-PB, identification was performed after isolation of the fungus. After the fungal growth on the plaques, the pathogen was identified through spore visualization under the optical microscope. To obtain a pure culture, the fungal colony was again re-plated and plated in BDA medium. For the reproduction of the symptoms, plastic vases containing autoclaved substrate were used, where 25 mL of the suspension containing 1 x 105 spores / mL of Fusarium sp. Were added. After the emergence of the seedlings, the reproduction of symptoms was observed. The fungus was re-isolated from the symptomatic plants, following the same procedure as above. As results, we could observe that the 4 stages of Koch Postulate were successfully fulfilled. That is, the fungus identified in the lesions was Fusarium sp. The same was isolated in pure culture. After inoculation of the healthy host, there was reproduction of the symptoms of tipping, and from the symptomatic plants the fungus was reisolated and presented the same characteristics of the original colony. It is concluded, therefore, that the causal agent of coriander seedling tipping in the municipality of Lagoa Seca - PB, is the fungus Fusarium sp.